This is a very detailed story from someone whose boots were on the ground.

On any given day, in any police department in the nation, 15 percent of officers will do the right thing no matter what is happening. Fifteen percent of officers will abuse their authority at every opportunity. The remaining 70 percent could go either way depending on whom they are working with.

That’s a theory from my friend K.L. Williams, who has trained thousands of officers around the country in use of force. Based on what I experienced as a black man serving in the St. Louis Police Department for five years, I agree with him. I worked with men and women who became cops for all the right reasons — they really wanted to help make their communities better. And I…